Contract law requires proof that the offeree 'intended' to accept the offer. It is not an uncommon defense for the offeree to allege that she did not intend to accept the offer. She might argue that she was only joking when assenting or that she didn't even know that an offer was being made, or that when signing the document she failed to read all of the terms, or that she did read all of the terms but did not understand certain ones. How would an offeror prove that the offeree did was bound by the offer and all of its terms if the offeree contended:
a) She was only joking: The offeror would argue that . . .
b) She didn't know that an offer was being made: The offeror would argue that . .
c) She knew she was signing an offer but he didn't read all of the terms: The offeror would argue that . . .
d) She did not understand some of the terms and conditions: The offeror would argue that . . .